LED flasher for battery cell-powered lamp

ABSTRACT

An LED flasher circuit is attached to a battery-cell-powered lamp and connected to the battery power source to provide a finding aid for the battery lamp in the dark.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to the use of an LED (light emitting diode) whichperiodically flashes "on" to aid in finding a battery cell-powered lampin the dark.

2. Description of the Prior Art

Incandescent "flasher" bulbs have been used in flashlights as disclosed,for example, in U.S. Pat. Nos. 3,053,978 and 3,609,344. The high currentdrain on the batteries, however, precludes the use of continuallyflashing "flasher" bulbs to function as a finding aid for locating abattery lamp in the dark.

The use of luminescent or phosphorescent material as an auxiliary lightsource has been suggested to aid in finding a flashlight in the dark asdisclosed, for example, in U.S. Pat. Nos. 1,285,382 and 4,052,610.However, the light emitted from such material is generally fairly dimand of a relatively constant intensity which is bound to be unnoticed.

SUMMARY OF THE INVENTION

One aspect of the present invention resides in the improvement to abattery cell-powered lamp having an auxiliary light source to aid infinding the lamp in the dark. The improvement comprises an LED flashercircuit attached to the battery cell-powered lamp wherein an LED isproximate the outer body of the lamp and wherein the LED flasher circuitis energized by a battery cell-power source of the lamp.

Another aspect of the present invention resides in providing aflashlight comprising: a body having a first end and a second end; anendcap which attaches to the body at the first end; a head whichattaches to the body at the second end; a module containing an LEDflasher circuit attached to an inside of the endcap wherein asubstantial portion of an LED is visible; a first conductor running froma switch for a lamp to a portion of the body proximate the first end; asecond conductor attached to the module, connected to the LED flashercircuit, adapted to be connected to a cathode of a cell, and having aportion which automatically connects to the first conductor when theendcap is attached to the body; a third conductor running substantiallyfrom the first end to the second end of the body; a fourth conductorlocated in the endcap, connected to the LED flasher circuit, and havinga portion which automatically connects to the third conductor when theendcap is attached to the body; and, connection means to automaticallyconnect the fourth conductor with a conducting member which is connectedto an anode terminal of the lamp.

It is accordingly an object of the present invention to provide a novelaid for finding a battery cell-powered lamp in the dark which includesthe use of an LED which periodically flashes "on".

Another object is to provide a novel, flashing, auxiliary light sourceto aid in the finding of a battery cell-powered lamp in the dark whichdraws a minute current compared with the main lamp.

Still another object is to provide a flashlight incorporating an LEDflasher circuit which allows convenient access to the battery cells andlamp.

Other objects and features of the invention will become apparent uponreading the description of the preferred embodiment in conjunction withthe drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a schematic diagram partially in block according to thepresent invention;

FIG. 2 is a sectional view of a flashlight incorporating the circuit ofFIG. 1; and

FIG. 3 is a front elevation of a battery cell-powered emergency walllamp incorporating the circuit of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Battery cell-powered LED flasher circuits are known in the art asdisclosed, for example, in U.S. Pat. No. 3,737,722 or in the descriptionof typical applications of a No. 3909 LED flasher/oscillator describedin Semiconductor Reference and Application Manual, 1978 edition, page45, published by Radio Shack, a Division of Tandy Corp., Fort Worth,Tex., herein incorporated by reference.

FIG. 1 shows circuitry making use of an LED flashing circuit. The anodeof LED 10 is connected to pin 6 of integrated circuit 11, which is a No.3909 integrated circuit as described in the above incorporatedreference. The cathode of LED 10 is connected both to pin 8 ofintegrated circuit 11 and to one side of capacitor 12. The other side ofcapacitor 12, which is the side with the positive voltage polarity, isconnected to pin 2 of integrated circuit 11. Capacitor 12 is suitably anelectrolytic type 300 uF capacitor with a 6-volt rating.

Conductor 13 connects pin 5 of integrated circuit 11 to the anode ofbattery 14. Conductor 15 connects pin 4 of integrated circuit 11 to thecathode of battery 14. Conductor 16 connects one terminal ofincandescent lamp 17 to the anode of battery 14. The other terminal ofincandescent lamp 17 is connected to the cathode of battery 14 throughconductor 18, switch 19, and conductor 20 respectively.

Battery 14 is suitably embodied as a pair of 1.5 volt flashlight batterycells placed in series so that the voltage at the anode of battery 14 isclose to 3 volts with respect to the cathode of battery 14. Incandescentlamp 17 is suitably embodied as a flashlight light bulb for thecorresponding battery or batteries which comprise battery 14.

With the circuit of FIG. 1, the average current drain from battery 14 topower the circuit is less than 1.0 milliamp. The normal flash rate forLED 10 is 1 hertz with a flash duration typically below 6 milliseconds.

FIG. 2 illustrates a flashlight incorporating the circuit of FIG. 1.Cells 21 and 22 are conventional 1.5 volt "D" cells placed in series andcomprise an embodiment of battery 14 of FIG. 1. Each terminal of LED 10is connected into control circuitry 23 (shown in FIG. 1) which isembodied as potted flasher circuit 51. Potted flasher circuit 51 isbonded to conducting plate 29 which in turn is bonded to the innersurface of endcap 24. The conducting path from potted flasher circuit 51to the anode of cell 22 includes metal ring 47 which is secured to theend of the male-threaded portion of body 37 adjacent endcap 24. Metalring 47 contacts conducting plate 29 when endcap 24 is screwed onto body37. Conducting plate 29 is connected to the circuitry within pottedflasher circuit 51. Metal strip 39 is secured to the inner wall of body37 and is directly connected to metal ring 47. Conducting plate 27 abutsthe anode of cell 22 and contacts contact 52, which is formed from oneend of metal strip 39, when head 36 is screwed onto body 37, thuscompleting the conducting path to the anode of cell 22.

The conducting path from potted flasher circuit 51 to the cathode ofcell 21 includes metal cap 25 which covers the surface of potted flashercircuit 51 facing the cathode of cell 21. Spring 28 is secured to metalcap 25 and provides a conducting path from metal cap 25 to the cathodeof cell 21. Metal cap 25 is connected to the circuitry within pottedflasher circuit 51, thus completing the conducting path to the cathodeof cell 21. To prevent metal cap 25 from contacting metal strip 39,plastic coating 48 insulates metal strip 39 in the vicinity of metal cap25.

The conducting path from the cathode of cell 21 to lamp 34 includesspring 28 and metal cap 25. Brush contact 50 is formed on metal strip 33by providing a curved bend whose convex portion contacts metal cap 25when endcap 24 is screwed onto body 37. Metal strip 33 is secured tobody 37 and terminates near switch 30. Metal strip 31 is attached toswitch 30 and contact 54, formed from one end of metal strip 31, ismoved thereby into contact with and out of contact with metal disk 32.Metal strip 31 always contacts metal strip 33 and slides against it whenmoved by switch 30. Metal disk 32 contacts the cathode terminal of lamp34, thus completing the conducting path to lamp 30.

Conducting plate 27 is a base member secured to plastic sleeve 35 whichscrews into metal disk 32 to hold lamp 34 stationary. With thisarrangement, head 36 may be unscrewed from body 37 to permit readyaccess to lamp 34 by unscrewing plastic sleeve 35. Likewise, endcap 24may be unscrewed from body 37 to permit ready access to cells 21 and 22.

FIG. 3 illustrates a battery cell-powered emergency wall lampincorporating the circuit of FIG. 1. Screws 40 through 43 hold theemergency wall lamp on a wall; alternatively, the wall lamp could behung on a bracket from a wall. Reflector 44 is suitably embodied as aconventional flashlight reflector. Incandescent lamp 45 and switch 46are specific embodiments of lamp 17 and switch 19 respectively shown inFIG. 1. Positioned proximate switch 46 is LED 10. Control circuitry 23is placed inside of the wall lamp. LED 10 is connected to controlcircuitry 23 and may be located directly on switch 46 as shown in FIG.3; alternatively, it may be placed near switch 46. Thus, one need onlyfind the flashing LED 10 in the dark and conveniently activate switch 46to turn "on" the wall lamp.

Other variations will occur to those skilled in the art such as the useof fluorescent lights for the main lamp and all such variations aredeemed to be within the scope of the appended claims except whereexpressly limited otherwise.

I claim:
 1. In a lamp powered by self-contained electric cells andhaving an auxiliary light source to aid in finding the lamp in the dark,the combination in said auxiliary light source comprising:(a) a flashercircuit contained within said lamp; (b) means automatically connectingsaid flasher circuit directly to said self-contained electric cells uponinstallation of said cells; and (c) a light-emitting diode mounted in avisible location at the outer body of said lamp and connected directlyto said flasher circuit, the flasher circuit being selected withcomponents to provide a flashing rate to said light-emitting diode of atleast 1 Hertz with an average current drain from said electric cells ofless than 1.0 milliamperes.
 2. The combination as claimed in claim 1wherein the lamp is a flashlight.
 3. The combination as claimed in claim1 wherein the lamp is an emergency wall lamp.
 4. The combination asclaimed in claim 3 wherein the LED is positioned proximate a switchwhich operates the emergency wall lamp.
 5. A flashlight comprising:(a) abody having a first end and a second end; (b) an endcap which attachesto the body at the first end; (c) a head which attaches to the body atthe second end; (d) a module containing an LED flasher circuit attachedto an inside of the endcap wherein a substantial portion of an LED isvisible; (e) a first conductor running from a switch for a lamp to aportion of the body proximate the first end; (f) a second conductorattached to the module, connected to the LED flasher circuit, adapted tobe connected to a cathode of a cell, and having a portion whichautomatically connects to the first conductor when the endcap isattached to the body; (g) a third conductor running substantially fromthe first end to the second end of the body; (h) a fourth conductorlocated in the endcap, connected to the LED flasher circuit, and havinga portion which automatically connects to the third conductor when theendcap is attached to the body; and (i) connection means toautomatically connect the fourth conductor with a conducting memberwhich is connected to an anode terminal of the lamp.
 6. A flashlight asclaimed in claim 5 wherein the LED flasher circuit is a semiconductorcircuit drawing less than 1.0 milliamp of average current.
 7. Thecombination as claimed in claims 2, 3, 4, or 1 wherein saidlight-emitting diode is connected to operate continuously while activeelectric cells are in said lamp.